Solid polymer electrolyte (SPE) cells refer to cells in which one or both electrodes are bonded to or embedded in a polymeric ion exchange membrane. Such cells are rather well known in the art and are discussed in detail in the following patents: U.S. Pat. No. 4,315,805 "Solid Polymer Electrolyte Chlor-Alkali Process", Darlington, et al. (Feb. 16, 1982); U.S. Pat. No. 4,364,815 "Solid Polymer Electrolyte Chlor-Alkali Process and Electrolytic Cell", Darlington, et al.(Dec. 12, 1982); U.S. Pat. No. 4,272,353 "Method of Making Solid Polymer Electrolyte Catalytic Electrodes and Electrodes Made Thereby", Lawrence, et al.(June 9, 1981; and U.S. Pat. No. 4,394,229 "Cathode Element For Solid Polymer Electrolyte", Korach (July 19, 1983).
In SPE cells, a current collector is pressed against and contacts the electrode and provides a pathway for electrical current to flow from a power supply to the electrode. Current collectors are electrically conductive, hydraulically permeable matrices which may take a variety of shapes, sizes, and types, including metallic window screen, punched metallic plates, expanded metals, and the like. The following patents describe some commonly-used types of current collectors: U.S. Pat. No. 4,299,674 "Process For Electrolyzing An Alkali Metal Halide Using A Solid Polymer Electrolyte Cell", Korach (Nov. 10, 1981); U.S. Pat. No. 4,468,311 "Electrolysis Cell", de Nora, et al. (Aug. 28, 1984); and U.S. Pat. No. 4,215,183 "Wet Proofed Conductive Current Collectors for the Electrochemical Cells", MacLeod (July 29, 1980).
SPE cells often have major problems due to the high electrical resistance between the embedded or bonded electrodes and the current collectors which are pressed against the electrode. Many workers in the art have attempted to solve the high resistance problem in a variety of ways. Some solutions include the use of a mattress as shown in U.S. Pat. No. 4,468,311 "Electrolysis Cell", de Nora, et al. (Aug. 28, 1984); applying the electrocatalyst directly to a conductive carbon cloth which acts as the current collector as shown in U.S. Pat. No. 4,239,396 "This Carbon-Cloth-Based Electrocatalytic Gas Diffusion Electrodes, And Electrochemical Cells Comprising the Same", Allen, et al. (Oct. 6, 1981).
The present invention provides a SPE structure that minimizes the electrical resistance between the current collector and the embedded or bonded electrode.